Setting up a Rover Base RTK System

Pages
Contributors: Nate
Favorited Favorite 9

Introduction

This tutorial will walk you through setting up a base and rover so that your rover can have the ~14mm accuracy that surveyors use! This can be useful for all sorts of projects including agriculture, drones, mapping, and even some extreme geocaching.

ZED-F9P connected via USB to SW Maps

The SW Maps app for Android connected to a ZED-F9P over USB C using RTK and a serial radio

We’ve been using the ZED-F9P from u-blox for a few years now. While it is a bit pricey (~$200) it is a fraction of the cost of other RTK systems ranging from $3,000 to $20,000 or more! The ZED-F9P is as impressively powerful as it is configurable. We will also be making liberal use of u-center from u-blox - don’t worry, we’ve got a tutorial for that. Unfortunately u-center is currently only for Windows. For the more adventurous, SparkFun has created a popular and powerful u-blox Arduino library that can do everything u-center can from an Arduino.

Quick note: You will see the terms GPS and GNSS used interchangeably throughout this tutorial. GNSS, or Global Navigation Satellite System, is the collective term for all GPS (USA), GLONASS (Russia), BeiDou (China), and Galileo (EU) satellites. GPS was the predominant constellation up to about 2017. After this time enough BeiDou satellites were functional and enough GLONASS satellites were transmitting additional bands (L2, etc) that advanced receivers are now designed to receive signals from a variety of constellations rather than just GPS. This is a very good thing. With more satellites and more frequencies we can improve accuracies greatly. Said differently, you don’t own a GPS receiver, you own a GNSS receiver. Congrats!

Do I really need RTK?

Great question. With a ZED-F9P and a u-blox L1/L2 antenna (and no RTK correction data) we’ve seen 30 or more satellites and horizontal positional accuracies better than 300mm. This is incredibly precise for a single receiver and should be adequate for many projects. RTK is a challenge to setup but once complete you should be able to obtain an RTK fix which has 14mm of accuracy (the precision is sub millimeter). To put the ZED-F9P in perspective, the SAM-M8Q is a great receiver, but can only receive L1 frequencies and has horizontal accuracy of 2.5m (2500mm). The ZED-F9P is far more accurate.

Note: It's best to get an RTK system worked out from the comfort of your desk. Don't go into the field with a laptop and try to get everything working outside.

Suggested Reading

Before getting started, be sure you are comfortable with Getting Started with U-Center and be sure to checkout our What is GPS RTK? tutorial.

I2C

An introduction to I2C, one of the main embedded communications protocols in use today.

What is GPS RTK?

Learn about the latest generation of GPS and GNSS receivers to get 14mm positional accuracy!

Getting Started with U-Center for u-blox

Learn the tips and tricks to use the u-blox software tool to configure your GPS receiver.

GPS-RTK2 Hookup Guide

Get precision down to the diameter of a dime with the new ZED-F9P from u-blox.